#include<vector>
using namespace std;

class Solution {
public:
    int maxProfit(vector<int>& nums) {
        int n = nums.size();
        vector<vector<int>>dp(n, vector<int>(3));
        dp[0][0] = -nums[0], dp[0][1] = 0, dp[0][2] = 0;
        for (int i = 1; i < n; i++) {
            dp[i][0] = max(dp[i - 1][0], dp[i - 1][1] - nums[i]);
            dp[i][1] = max(dp[i - 1][1], dp[i - 1][2]);
            dp[i][2] = dp[i - 1][0] + nums[i];
        }
        return max(dp[n - 1][0], max(dp[n - 1][1], dp[n - 1][2]));
    }
};